Power driven hammer

ABSTRACT

An automatic nailing machine having a vertically reciprocable hammer normally urged downwardly, liftable by a motor-driven pinion twice each revolution of the pinion, normally latched in its upright cocked position but releasable by the pinion when a hand-operated trigger is actuated, for intermittent or repeated hammering operations. The hammer head is removable from the hammer slide.

1 fl ,2 I Untte States atent 1191 1111 3 84x322 Smith 1 1 Nov. 112 1197471 POWER DRIVEN HAMMER 3589.588 6/1971 Vzisku 227/131 [76] Inventor:Howard 1. Smith, 2546 Willow Ln..,

A ld M 63010 Primary Examiner-Granville Y. Custer Jr. Filed p w 1973Attorney, Agent, or Firm-Rogers, Ezcll & Eilers [21] Appl. No: 396,047[57] ABSTRACT An automatic nailing machine having a vertically re-..227/l3l2li2252c7/11/5Nl5 ciprocable hammer normally urged downwardlymp able by a motor-driven pinion twice each revolution of [58] Field ofSearch 227/131, 132 the pinion, normally latched in its upright cocked psition but releasable by the pinion when a hand- [56] References Citedoperated trigger is actuated, for intermittent or re UNITED STATESPATENTS peated hammering operations. The hammer head is 1,763,285 6/1930Shallenberger .v 227/131 removable from the hammer slide. L84 l7 2/1932Metcalf 227/131 3 305 156 2/1967 Khan .1 227/131 12 Claims, 8 DrawinglFigures PATENTEDHUV 12 1974 Q 38 41322 saw 2 or 3 POWER DRIVEN HAMMERBACKGROUND OF THE INVENTION Heretofore power driven hammers have beenpro vided wherein the hammer is retracted by a motor and means areprovided to de-energize the motor after a hammer movement to'preventrepeated movement.

In the present device, the cycle provides for continuous repeatingoperation at will or intermittent operation at will, and in both casesthe control is mechanical without requiring starting and stopping of theelectric motor drive. While this concept is broadly shown in prior art,in the present arrangement, the manually operated trigger only releasesthe trip mechanism so that it can be operated by the pinion. By thisconstruction, there can be no manual release of the hammer that permitsit to descend by the spring and crash against the gearing. Also therecan be no hazardous accidental release of the hammer if its motor hasbeen turned off adjusted to take up wear should .it occur. The hammerelement itself can be replaced.

Inthe drawings: FIG. 1 is an elevation of the hammer with one side panelremoved and with some parts shown in section;

FIG. 2 is an enlarged section taken on the line 2-2 ofFlG. l; I I 1 FIG.3 is a bottom view with the bottom panel removed; I y j FIG. 4 is an endview from the right end of FIG. 1 with the end panel removed and otherparts shown in section; I

FIG. 5 is a vertical section through the latch mechanism taken onthelineS-S of FIG. I;

I FIG. 6is another vertical section through the latch mechanism taken onthe line 66 of FIG. 1; I

FIG. 7 is a third vertical section through the latch mechanism taken onthe line 7- -7 of FIG. 1; and

FIG. 8 is anenlarged elevation of the latch mechanism.

The hammer may be constructed with a casing 10 here shown as being abox-like construction. It has panels that are removable to give accessto the interior, and

. are held in place by screws (not shown) or like attachment devices.Externally the housing also has a carrying handle Ill.

Power is supplied by a motor 12 mounted on a U- The shaft 17 drives aworm wheel 21 that meshes with a pinion 22 that is mounted on a crossshaft 23 having bearings in the front wall 25 and the rear wall 14 ofthe housing 10. There is a switch 26 constituting a master control forthe motor, and hence for the hammer. Thus operation of the motor 12through the belt and pulley 19 drives the shaft 17, the worm gear 21,and the pinion 22. I a

The front face' of the pinion 22 has two arcuate racks or gear segments28 projecting from its forward face, as shown. Each of these arcuateracks in turn can engage a linear rack 30 that is partof the hammersubassembly generally indicated at 31.

This hammer subassembly includes a strong, approximately square column36 welded or otherwise secured to the top panel 37 and to the bottompanel 38 of the housing. The column 36 is shown as having flanges at itsbottom and top that are bolted to the wall panels (see FIG. 2).

A hammer slide 42 has a free sliding movement vertically on the column36. The slide 42 is likewise noncircular so that it will not twist onthe column, and is here shown as being approximately square in crosssection. The back wall 43 of the hammer slide projects outwardly a shortdistance at one edge (FIG. 2) and has the linear rack 30 on it inposition to mesh with either of the two arcuate racks128, that'projectfrom the face of the pinion 22. The front wall 45 of the hammer slideprojects out at the opposite edge whereto a removable hammer 46 isattached by screws -47. This hammer has a depending head 48 that islocated above the endof a conventional 'nail magazine diagrammaticallyillustrated at 49. As is known in the art, the nails N are fed to theright in FIG. 2 by a spring mechanism 50 so that there is a nail to bedriven in position underthe hammer head 48. Noting FIGS. 2, 3 and 4, themagazine 49 holds the headed nails Non a slotted track, the nails beingurged one at a time to the position under the head 48 by the spring andpresser assemblyg50. This mechanism can be like that in a conventionalstapler.

. The hammer head 48 is removablebecause it constitutes a wear member.This is accomplished by remov bracket 13 secured as by welding to theback wall 14 of the housing 10. A medial partition wall 15 extendsacross theinterior ofthe housing adjacent one end of the motor 12. Theworm shaftl7 is mounted in bearings in the partition 15 and an end wall18 of the housing 10. A belt and pulley arrangement 19 connects themotor 12 to the shaft 17 for operation of the shaft by ing the'screws47. r e I Removing the screws 47 removes the hammer 46 of which thehammer head 48 is a part, so that removal of the screws ultimatelyresults in removal of the hammer head.

A coil spring 52 is a tension spring that draws the hammer slide 42downwardly sharply. The spring 52 is anchored atits lower end by a clipassembly 53 and at its upper end it is held by a pin 54 that spans andis secured to the upper end of the slide 42. To accommodate the pinduring descent of the slide 42, the column 36 has opposite slots 56. p

A releasable latch means is provided to hold the ham mer in its cockedposition but to prevent it from moving to the nail'driving position. Theupper end of the linear rack 30 has a projecting tooth, orlatching lug,60. This lug 60 should be displaced forwardly (in FIG. 1) from the rack30 so as not to interfere with the racks 28. This is illustrated in FIG.4. Adjacent this lug 60 in its upper position there is a bracket 61attached to the top wall 37 and depending therefrom. The bracket.6lsupports a sliding latch bar 62, the end of which can project under thelatching tooth 60. These members are sloping so that as the slide 42comes up, the upper filled with nails, spikes or the like which disposesone in the path of the hammer 48, and will move an additional one intoplace as soon as the first one is driven and the hammer is withdrawn.The nailing machine is duly connected to a source of electric power andthe switch 26 operated to energize the motor. When this and a collar 64that is fixed to the bar 62. As shown in time for a nailing descent ofthe hammer.

A trigger means is provided to enable the pinion to release the hammer,whenever a hammer action is desired. A longleve'r 67 is pivoted at 68 tothe side of the bracket 61. It depends to one side of the bar 62 anddown adjacent one face of the pinion 22, but above the arcuate racks 28.This lever is normally urged to the right in FIGS. 1' and 8 by a coilspring 70 that extends between the lever 67 and the bracket 61. Thelever 67 mayengage a pin 72 attached to the rod 62 to limit the amountof counterclockwise rotation of the lever 67.

The lever 67 normally can swing freely to the left from the positionindicated in FIGS. 1 and 8, in the sense that such movement is notobstructed by a stop, to be described. It depends at its lower end intothe path of earns 75 that project outwardly from the face of the pinion22. Either of these cams can engage the depending end of the arm 67 andswing the arm about its pivot 68in a clockwise direction in FIGS. 1 and8. If the trigger mechanism to be described is in the normal untriggeredposition, this swinging will not move the bar 62 or remove its end frombeneath the tooth 60. As rotation of the pinion 22 proceeds, the camswings out from under the tapered end of the arm 67, whereupon thespring'70 will cause the arm to move back counterclockwise until stoppedby the pin 72 projecting from the rod 62.

Manually controlled means are provided to cause the hammer to be drivendown by its spring 52. Adjacent the upper end of the handle 11 on thetop of the housing 10, there is a trigger 80 pivoted to the handle at 81for rocking movement. A rod 82 is pivotally attached to the trigger 80and depends through an opening in the top wall 37 to engage and bepivoted in a stoplink 83. A coil spring 84 acts between the undersurfaceof the top wall 37 and an appropriate washer 85, to urge the link 82downwardly. The stop link 83 is swivelled at 86 to the collar 64 that isattached to the rod 62. Thus when the trigger 80 is squeezed by the handengaging the handle 11, and its end is pulled upwardly, the link 82 ispulled upwardly and the stop link 83 swivelled clockwise about the pivot86 until its right-hand end is within the path of the long arm 67, asshown in dashed lines in the drawing; The engagement of the lower end ofthe lever 67 by one of the cams 75 rocks that lever clockwise. Sincethat lever is then in engagement with the stop link 83,.it pushes on theend of the stop link, thereby pushing the collar 64 that in turn issecured to the rod 62, moving the rod 62 to the left against the spring63 and withdrawing its right end from the tooth 60. When this occurs,the hammer is forcefully drawn downwardly by the spring 52 and drivesthe nail.

OVERALL OPERATION As it is understood in the art, the magazine 49 isduly occurs, the pulley and belt arrangement 19 will drive the shaft 17and through the worm gear 21 will rotate the pinion 22. Assuming thehammer to have been at its lower position, the rotation of the pinion 22will cause one of the arcuate racks 28 to engage the linear rack 30 andmove it upwardly, the pinion 22 moving counterclockwise in FIG. 1. Atthe upper end of its movement, the hammer 42 will bring the tooth 60into engagement with the sloping end of the bar 62 displacing the bar 62away until the tooth 60 has moved to above the bar, whereupon the spring63 will force the bar to the right again under the tooth 60 to hold thehammer in its upper position where it is cocked for a hammeringoperation.

If the operator has not at this time squeezed the trigger 80 upwardly,the stop link 83 will be in the position of FIG. 8 rather than in theposition of FIG. 1. Shortly after the arcuate cam 28 has moved beyondthe position where it lifts the hammer 42, the cam 75 on the face of thepinion 22 will engage the lower end of the long link 67 and rock thatlink clockwise about its pivot 68. With the toplink 83 in its upperposition of FIG. 8, the long lever 67 merely rocks about the pivotwithout performing any work, until the cam 75 moves from under thebottom of the lever 67 permitting the spring to return that lever to itsposition against the pin 72. Continued rotation of the pinion 22 willmerely repeat the rocking of the lever'67 but no hammering action willoccur.

In order to have a hammering action, the user squeezes the trigger 80upwardly. This draws on the rod 82 and rocks the stop link 83 down tothe dashed line position of FIG. 8 and the full line position of FIG. 1.This is an enabling action which conditions the latch mechanism forrelease, but does not actually perform the release. Only when the pinion22 revolves to a position wherein a cam can engage the lower end of thelong lever 67 does the release take place. When this happens, the cam 75moves the lower end of the lever 67, which 'now pushes leftward on theend of the stop link 83 that is pivotally connected at 86 to the collar64 attached to the latch rod 62, which is thus moved to release thetooth 60 on the hammer 42. The hammer then rapidly descends under theaction of the spring 52, causing a nail to be driven.

As soon as the cam 75 passes beyond the end of the lever 67, that leveris again released. If the trigger is held squeezed, the spring 63,acting through the pivot 86 and the stop link 83pushes the rod 62 backto the position for future latching. If the trigger 80 is released,however, so that the stop link 83 can move to its full line position inFIG. 8, nevertheless, the rod 62 is moved back by the spring 63 and thelever 67 is moved back by the spring 70 to the latching position.

If the trigger 80 is held squeezed through repeated revolutions of thepinion 22, there will be repeated nailing, with two nails being drivenfor each rotation of the pinion. In this case, the stop link 83 simplystays down in position to be engaged by the lever 67.

If wear occurs in the trigger mechanism parts 67 and 83, the collar 64can berepositioned on the rod 62 to accommodate such wear. Also thehammer element 46 can be removed by removing the screws it? and anotherhammer installed in the event the hammer is damaged or worn.

The advantages of the present construction include the mechanism bywhich the trigger operation only conditions the mechanism for release ofthe hammer, the release to be effected by one of the cams 75.. If thetrigger 8d, whenever operated to a release position, permitted thehammer to go down, the descent could occur while one of the arcuateracks 28 is in a half-way position, causing the hammer to strike therack with severe force and perhaps damage the teeth. Of greaterimportance is the safety factor. If the trigger is released at a timewhen the motor 12 is not running, there is practically no possibility ofhaving the hammer released to drive a nail. It will be recognized thatif, for example, the apparatus is set to one side in a cocked condition,it would be a serious hazard if a release of the trigger could cause thedriving of a nail. A person might set the apparatus down on a finishedsurface or even near or on a human being whereupon the driving of thenail would have serious consequences.

It is also notable that the present equipment is compact, but can beused for heavy-duty nailing. Having the arcuate gears and cams on thepinion face saves space and having the trigger mechanism in the samegeneral area likewise saves space. The use of the strong column 36 of anuncircular nature, especially a square shape in cross section, and asimilar shape to the nail slide itself provides a very strong structure.

Various changes and modifications may be made within this invention aswill be readily apparent to those skilled in the art. Such changes andmodifications are within the scope and teaching of this invention as defined by the claims appended hereto.

What is claimed is:

t. In a power hammer: a rotary driving element; a base support; a hammermember slidably mounted on the support for movements from a cockedposition in a driving direction; spring means to move the hammer memberin the driving direction; releasable latch means on the support andengageable with the hammer member to hold the hammer member in cockedposition against the spring means; and latch release means on thesupport to move the latch means to release position, the latch releasemeans including means driven by the driving element, and manuallyoperable means to connect or disconnect the means driven by the drivingelement to the latch means to cause the driving element to move thelatch means to release position.

2. In the hammer of claim ll: the manually operable means including atrigger, a stop link movable by movement of the trigger to a firstposition between the means driven by the driving element and the latchmeans to drivingly connect them, and to a second position that does notconnect them, whereby the driving element can be connected ordisconnected from the latch means depending upon the position of thetrigger.

3. in the hammer of claim 2: the driving element including a pinion gearhaving a driving connection to the hammer member, the means driven bythe driving element including a rocking link extending adjacent thepinion, and cam means on the pinion engageable with the link to displacethe link upon rotation of the pinion, the stop link being engageable bythe rocking link.

t. In the hammer of claim 3, the stop link being supported on the latchmeans, and movable therewith.

5. In the hammer of claim 4, the latch means comprising a slide bar andyieldable means urging the bar into latching position.

b. In the hammer of claim l: the driving element comprising a pinionhaving a gear-tooth arrangement for moving the hammer in one direction,in the form of two angularly spaced arcuate gear sets beside the face ofthe pinion and connected for rotation with it, and a rack on the hammermember engageable by each gear set for lifting the hammer member againstthe spring means; and the latch release means including a memberdepending alongside the face of the pinion, and cam means associatedwith each gear set for displacing the depending member at the end ofeach elevation of the hammer by such gear set.

'7. In the hammer of claim 6, the arcuate gear sets being supported on aface of the pinion, the cam means being two cams also on a face of thepinion and each having such angular relationship to a gear set that itcan actuate the latch release just after the hammer is fully raisedagainst the spring means.

8. In the hammer of claim 1: the hammer member comprising a slide and ahammer head removably secured to the slide.

9.. In the hammer of claim 11: a vertical column, the hammer membercomprising a hammer slide mounted for reciprocation on the column, thecolumn and slide being non-circular in cross section and complementary,to permit the reciprocation but prevent twisting of the slide about thecolumn.

MB. In the hammer of claim 9, the column being hollow, and the springmeans being a coil spring confined in the column.

' Iii. In a power hammer: a housing; a column in the housing; a hammerslide supported on the column for reciprocating movement thereon; ahammerhead on the slide;spring means urging the slide in a hammerdrivingdirection; a rack on the slide, a gear having arcuate, angularly spacedgear sets engageable with the rack on the slide during rotation of thegear to displace the slide against the spring means, the angular spacesbetween the gear sets affording intervals for return of the hammer bythe spring means; and releasable latch means for holding the slide inits displaced position against the spring means, the latch meansincluding interengageable latching elements the first of which isattached to the slide and the second is movably mounted on the housingfor displacement to and from engagement with the first; selectivelyoperable means to produce interconnection between the second latchingelement and the gear to cause the gear to disengage the .latchingelements in a predetermined relation to the position of the rack, toprevent release of the latch and the hammer slide when an angular spaceis presented to the rack so as to prevent clash of the slide rack andthe gear sets.

l2. In the hammer of claim 1111, the column and slide being non-circularto permit the reciprocation but pre-' vent relative twisting.

1. In a power hammer: a rotary driving element; a base support; a hammermember slidably mounted on the support for movements from a cockedposition in a driving direction; spring means to move the hammer memberin the driving direction; releasable latch means on the support andengageable with the hammer member to hold the hammer member in cockedposition against the spring means; and latch release means on thesupport to move the latch means to release position, the latch releasemeans including means driven by the driving element, and manuallyoperable means to connect or disconnect the means driven by the drivingelement to the latch means to cause the driving element to move thelatch means to release position.
 2. In the hammer of claim 1: themanually operable means including a trigger, a stop link movable bymovement of the trigger to a first position between the means driven bythe driving element and the latch means to drivingly connect them, andto a second position that does not connect them, whereby the drivingelement can be connected or disconnected from the latch means dependingupon the position of the trigger.
 3. In the hammer of claim 2: thedriving element including a pinion gear having a driving connection tothe hammer member, the means driven by the driving element including arocking link extending adjacent the pinion, and cam means on the pinionengageable with the link to displace the link upon rotation of thepinion, the stop link being engageable by the rocking link.
 4. In thehammer of claim 3, the stop link being supported on the latch means, andmovable therewith.
 5. In the hammer of claim 4, the latch meanscomprising a slide bar and yieldable means urging the bar into latchingposition.
 6. In the hammer of claim 1: the driving element comprising apinion having a gear-tooth arrangement for moving the hammer in onedirection, in the form of two angularly spaced arcuate gear sets besidethe face of the pinion and connected for rotation with it, and a rack onthe hammer member engageable by each gear set for lifting the hammermember against the spring means; and the latch release means including amember depending alongside the face of the pinion, and cam meansassociated with each gear set for displacing the depending member at theend of each elevation of the hammer by such gear set.
 7. In the hammerof claim 6, the arcuate gear sets being supported on a face of thepinion, the cam means being two cams also on a face of the pinion andeach having such angular relationship to a gear set that it can actuatethe latch release just after the hammer is fully raised against thespring means.
 8. In the hammer of claim 1: the hammer member comprisinga slide and a hammer head removably secured to the slide.
 9. In thehammer of claim 1: a vertical column, the hammer member comprising ahammer slide mounted for reciprocation on the column, the column andslide being non-circular in cross section and complementary, to permitthe reciprocation but prevent twisting of the slide about the column.10. In the hammer of claim 9, the column being hollow, and the springmeans being a coil spring confined in the column.
 11. In a power hammer:a housing; a column in the housing; a hammer slide supported on thecolumn for reciprocating movement thereon; a hammer head on the slide;spring means urging the slide in a hammer-driving direction; a rack onthe slide, a gear having arcuate, angularly spaced gear sets engageablewith the rack on the slide during rotation of the gear to displace theslide against the spring means, the angular spaces between the gear setsaffording intervals for return of the hammer by the spring means; andreleasable latch means for holding the slide in its displaced positionagainst the spring means, the latch means including interengageablelatching elements the first of which is attached to the slide and thesecond is movably mounted on the housing for displacement to and fromengagement with the first; selectively operable means to produceinterconnection between the second latching element and the gear tocause the gear to disengage the latching elements in a predeterminedrelation to the position of the rack, to prevent release of the latchand the hammer slide when an angular space is presented to the rack soas to prevent clash of the slide rack and the gear sets.
 12. In thehammer of claim 11, the column and slide being non-circular to permitthe reciprocation but prevent relative twisting.